In order to carry out or repeat the grinding of cylindrical objects, for example cylindrical workpieces forming the rolls of rolling mills and the like, in an automatic cycle without operators, it is necessary to effect tracing of the geometry and monitoring of the surface condition of the workpiece during grinding in order to influence the grinding cycle in progress as a function of these measurements and to guarantee the maximum precision demanded for such work.
Such operations are carried out by means of transducers operating both in contact with the surface and at a distance from it (i.e. contactless sensors), in which, in the case of known grinding machines, are mounted on the moveable carriage supporting the grinding tool, and scan the surface following the movement of the tool.
This means that the speed of scanning the workpiece and the speed of machining it must be the same. However, some types of tracing require scanning times substantially longer than the times required for the tool to perform a grinding pass and, therefore, it is necessary either to reduce the grinding speed to adapt it to the speed required by the tracing devices, with a consequent prolongment in grinding times, or to carry out only a partial tracing of the piece with incomplete scanning of its surface during each pass by the tool, arriving at its complete tracing by statistical means after a number of passes.
Furthermore, the positioning of measuring instruments in the vicinity of the tool may lead to a reduction in the life of such devices, owing to the presence of swarf and of vapors caused by the grinding process. In addition, it is possible for vibration to occur in the carriage carrying the tool as a result of the grinding operation, and such vibration may be transferred to the measuring instruments, reducing the precision of the measurements registered by them, when these instruments are mounted on the tool carriage.